Blanking die



Oct. 14, 1941-. A. H. BROWN 2,258,843

INVENT OR. ARTHUR H BROWN atentec ct. i4,

.NT OFFICE BLANKING .DIE

Arthur H. Brown, Denver, Colo. Application september 16, 1940, serialNo. 356,911 `t claims. (c1. 164-119) rIhis invention relates toimprovements in blanking dies and refers more particularly to a die forcutting openings of a predetermined size and shape in cardboard.

For diagnostic and operative purposes dentists find it essential to haveX-ray pictures made of theirclients jaws and teeth to determine theshape of the roots and whetheror not there are abscesses or other faultspresent.

A dental X-ray mount consists of a sheet of suitable material, usuallyCelluloid or cardboard, with openings (windows) of different sizes andin suitable arrangement cut therein so constructed as to receive andretain dental X-ray negatives in proper relations.

Mounts of several designs (arrangement of windows in differentcombinations of sizes and arrangement as to horizontal and verticaldisposition) are on the market but the number of designs would have tobe almost infinite to meet the requirements of all cases. Itis-necessary therefore, that a simple means be provided for quicklymaking mounts adaptable to any given case.

It is obvious that, in order to obtain satisfactory results from suchmounts, the negative and the opening must be cut to predetermined sizesand to assure this the openings in the cardboard must be cut by means ofblanking dies. Where large punch presses are employed the dies are ofusual construction and present no particular diiculty.

Dentists who make their own X-ray pictures as well as those whospecialize in this work and do it for others do not have powerfulpresses and f must therefore employ specially constructed blanking diesfor making them which may be used with small hand operated presses.

It is the object of this invention to produce simple vand reliableblanking dies of such construction that the parts will positively remainin alignment during the entire life of the die.

Another object is to produce a blanking die comprising a base which isthe female die and a resilient jaw having one end autogenously welded toone end of the base and to the underside of the free end of which themale die is rmly attached, thereby forming a unitary assembly which willpositively retain its alignment.

It is also desirable in dies of this type that the cutting edges of themale and the female dies shall approach each other in substantialparallel alignment and Vfor this purpose the resilient jaw that carriesthe male die is made upwardly concave to compensate for the flexure towhich it is subjected during operation.

The above and any other objects that may become apparent as thisdescription prcoeeds are attained by means of a combination and anarrangement of parts that will now be described in detail and for thispurpose reference will be 4had to `the accompanying drawing in which theinvention has been illustrated, and in which:

Eigure V1 is atop plan View of the banking die;

Figure 2 is an Aend elevationthereof; y

Figure 3 is -a longitudinal section taken on line 3-,Figure1; and e eFigure 4; isa bottom plan View of the die.

In the drawing reference numeral 5 Vdesignates a base which ispreferably made from Avtool steel and which, in the embodiment'sho'wn,is rectangular in shape. The shape of the base is, however, immaterialso far as the invention is concerned. K Y

Secured to the base is a jaw .6 which is made from eXible resilientmetal such as spring steel, but may be made of any other suitablematerial. In the embodiment illustrated, the jawis provided with an endportion l of substantially the same width-as the base and which isoffset from the jaw as shown in Figure 2'. The offset end is connectedwith the remainder of the jaw by means of an inclined portion 8. Theoilisetr end` 'i is firmly attached or lwelded to the end ofthe base `asby spotwelding `or by electrowelding. From the upper end of theinclinedportion 8, `the jaw preferably tapers and terminates at 9`which, in the embodiment illustrated, is slightly spaced from the end ofthe base. The base is provided with an opening I0 which, in theembodiment illustrated, kis substantially rectangular and has roundedcorners H and is provided on each side and end with two U or V-shapednotches l2. Secured to the under surface of the jaw is a male die I3Vwhose shape and size is substantially identical with the opening Ill.The male ydie is preferablyA made from tool steel so as to preserve itsvcutting edge as long -as possible, but may be made from any othermaterial that may be found preferable or more desirable for thispurpose. The jaw 6 is biased away from the upper surface of the `base inthe manner shown in Figure 2 and is spaced therefrom suciently to permita card- -board I4 to b e inserted intoposition for being perforatedv bythe die. The two` jaws of the die are moved towards each other by meansof a suitable press which has not been shown, but the base of the presshas been indicated by a broken line and designated by reference numeralI5, similarly the plunger or movable part of the press has been shown bybroken lines and designated by reference numeral I6.

Assuming now that the parts are in the position shown in Figure 3 andthat plunger I6 is moved downwardly, it will rst of all engage -theupper surface of jaw 6 and will then move the latter downwardly intoengagement with the cardboard or other sheet' materialv I4 vwhich is tobe blanked. 'I'he curvature of jaw 6 is such that due to the ilexurewhich takes place on account of its cantilever action, the inner surfaceof the male die becomes substantially parallel with the upper surface ofthe base when the male die contacts the upper surface of the cardboard.As the pressure increases the male die will continue its downwardmovement and shear the cardboard forming an opening therein of the exactshape and size desired. When the pressure is removed from the jaw, itsresiliency will cause the male die to be withdrawn from the opening andthe parts will then be in position to .repeat the operation.

In order to obtain the parallel position of the cutting edge of the maledie to that of the female die, the jaw has been bent along the line I1so that the part between the inclined wall 8 and line ll makes a slightangle with that part of the jaw that extends to the right of line IT.,This angle has been designated by letter w in Figure 3. Since the jawis of the cantilever type and autogenously joined to the base, it isevident that it will flex in response to the pressure exerted on it byplunger I6 and by making the jaw upwardly concave and proportioning thecurvature to the flexure that results from the bending force applied tothe jaw, the curvature and the flexure may be so proportioned that themale die will assume a position substantially parallel to the uppersurface of the base as it comes into contact with the paper or othersheet material to be slieared. Although the parallel relationship justexplained is desirable and is sought to be obtained, it is evident thata slight variation such as a few thousandths of an inch is not ofmaterial consequence and therefore the statement that the male diebecomes parallel with the upper surface of the base must be consideredwithin reasonable limits,

It will be observed that the jaw is made of sheet metal of considerablewidth and since the end 'I is welded to the base, the alignment willremain as originally constructed during the entire life of the die asthe jaw cannot move sidewise without bending in the direction of itsplane. Since the jaw is wide in proportion to its thickness, bendingwill not take place under ordinary conditions. It is doubtful whethersuiicient force can be exerted on the jaw to bend it in the direction ofits width without breaking the connection between it and the base. Whenthe male die I3 is spot welded to the inner surface of the jaw, itcannot accidentally move relative thereto and the three parts onceproperly aligned will therefore retain their alignment during the lifeof the die, regardless of the amount of work accomplished by the latter.

I am aware that blanking dies of somewhat similar construction have beenmade in which the jaw and the base are connected by ordinary hinges oiby a curved spring strip. Such dies will not positively retain theiralignment because the hinges will wear and only a slight wear will beSufficient to displace the male die with respect to the opening andinterfere with the successful operation. Where the two parts are joinedby curved springs, as has been suggested, the jaw can readily be movedtransversely and if submitted to sufficient pressure to give the springa permanent set, the die will be ruined for further use.

The autogenous connection between the jaw and the base has beenparticularly pointed out for the reason that such a connection is ofgreat importance in a die of this type as by this means positivealignment is assured. When the two parts are connected by screws orrivets, there is always a possibility of relative displacement as theinterconnection between the fastening means and the base and jaw willnearly always permit of microscopic movements sufficient to interferewith the successful operation of the die. The offset of the jaw relativeto the base is also of importance because by this means the male diemember will more readily assume a position parallel with the suppersurface of the base and provides space for the reception of thecardboard I4. The upward concavity of the jaw is also of importance inthis combination for reasons already pointed out as by thus bending thejaw a proper degree, the parallel positioning of the two dies willautomatically take place and as a result of this a more eiicientoperation and a cleaner cut opening is obtained.

In the embodiment illustrated, the die is designed to cut opening incardboard for the reception of X-ray films, but it is evident that theshape of the opening I0 can be varied from that shown in the drawing andthe die illustrated can be used for many other purposes than the onepointed out as the primary purpose, and the shape of the die opening istherefore to be considered as illustrative only and not in any way as alimitation.

Dies constructed as above described can be readily substituted for eachother in the press and positioned to make all the windows in alignment.

Having described the invention what is claimed as new is:

l. A blanking die comprising, a base having an opening forming a femaledie, a flexible resilL ient jaw member of substantially greater widththan thickness having one end rigidly attached to one end of the base,the end attached to the base being offset to space the under side of thejaw from the base, the free end of the jaw having a male die secured tothe under surface of the movable end thereof in position to cooperatewith the female die in the base, that portion of the flexible jawbetween the offset portion and the male die being upwardly concave, thecurvature compensating for the flexure of the jaw in its movementtowards the base whereby the two cutting edges of the dies will approacheach other in substantially parallel relation.

2. A blanking die comprising, a base having an opening forming a femaledie, a flexible resilient jaw of substantially greater width thanthickness having one end autogenously welded to the upper surface of thebase, the under surface of the jaw being spaced from the upper surfaceof the base from its point of attachment thereto to its free end, a maledie member immovably attached to the under surface of the free end ofthe jaw in position to enter the die opening in the base when the jaw isflexed toward the latter, that portion of the jaw between its point ofattachment to the base and the adjacent edge of the male die beingupwardly concave whereby the cutting edge of the male die will beupwardly inclined with respect to the upper surface of the base when theparts are in normal position and whereby the cutting edges of the dieswill approach parallelism as the jaw is eXed in its movement towards thebase.

ARTHUR H. BROWN.

